"Lost in You" is the fourth single released from Three Days Grace's third album, Life Starts Now. The song was released for radio air play on February 1, 2011. Much like "Never Too Late", it was a crossover song to top 40 radio. The song is also the band's first entry into adult contemporary stations; the first stations being on CFIT-FM Calgary, CKSY-FM Chatham-Kent, CJRL-FM Kenora & WNIC Detroit.
"Lost in You" is considered somewhat unusual for the band. The song expresses a more affectionate sentiment than is typically found in the band's music. While electric guitars still play a prominent role, the focus is on Adam Gontier's voice and the melody.
The song, unlike much of the band's other works, is quite positive.
It is a song written with simple words: "Let me inside, let me get close to you / Change your mind, I'll get lost if you want me to / Somehow I found a way to get lost in you." The lyrics are bittersweet as Gontier sings about a love that has its ups and downs.
On March 15, 2011, the band released an EP, via online download, containing the piano version of "World So Cold" and a cover of the Fleetwood Mac song "The Chain" in promotion of "Lost in You".